There are known thermoplastic elastomer compositions having an excellent balance of air permeation resistance and flexibility, the compositions being obtained by dispersing a specific elastomer component into a specific thermoplastic resin matrix as a discontinuous phase (Japanese Unexamined Patent Application No. H08-259741A).
For example, a thermoplastic resin elastomer composition produced by melt-kneading a modified polyamide resin, an ethylene-vinyl alcohol copolymer, and a maleic anhydride modified ethylene-propylene copolymer with a twin screw kneader and an example in which a pneumatic tire using a film consisting of the composition as an inner liner is produced have been reported (Japanese Unexamined Patent Application Publication No. 2010-132850A).
The elastomer component in a thermoplastic elastomer composition originally has an effect of improving the low-temperature durability of the thermoplastic elastomer composition. However, when producing an thermoplastic elastomer composition by melt-kneading a thermoplastic resin and an elastomer with a twin screw kneader, there has been a problem in that simply increasing the elastomer ratio causes the proportion of coarse elastomer particles to increase without the elastomer being finely dispersed in the thermoplastic resin, which prevents the original low-temperature durability improving effect from being sufficiently expressed.